/* ============================================================
   Double-Slit Experiment — style.css
   Tablet-friendly dark theme
   ============================================================ */

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:        #0d1117;
  --surface:   #161b22;
  --surface2:  #1f2937;
  --border:    #30363d;
  --accent:    #58a6ff;
  --accent2:   #3fb950;
  --text:      #c9d1d9;
  --text-muted:#8b949e;
  --danger:    #f85149;
  --radius:    8px;
  --font:      -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

html, body {
  height: 100%;
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  overflow: hidden;
}

/* ── Header ─────────────────────────────────────────────── */
header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 16px;
  height: 52px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

.header-left { display: flex; align-items: center; gap: 12px; }

h1 {
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--accent);
  letter-spacing: 0.01em;
}

.subtitle {
  font-size: 0.78rem;
  color: var(--text-muted);
  display: none;
}
@media (min-width: 600px) { .subtitle { display: inline; } }

.lang-group { display: flex; gap: 6px; }
.lang-btn {
  padding: 5px 10px;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--text-muted);
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 0.82rem;
  font-weight: 500;
  transition: all 0.15s;
}
.lang-btn:hover  { border-color: var(--accent); color: var(--accent); }
.lang-btn.active { background: var(--accent); color: var(--bg); border-color: var(--accent); }

/* ── App shell ───────────────────────────────────────────── */
#app {
  display: flex;
  flex-direction: column;
  height: calc(100vh - 52px);
  overflow: hidden;
}

/* ── Experiment canvas area ──────────────────────────────── */
#canvas-area {
  flex: 1 1 auto;
  min-height: 0;
  position: relative;
  background: #050810;
}

#experimentCanvas {
  display: block;
  width: 100%;
  height: 100%;
}

/* Canvas overlay labels */
.canvas-label {
  position: absolute;
  font-size: 0.7rem;
  color: var(--text-muted);
  pointer-events: none;
  background: rgba(5,8,16,0.7);
  padding: 2px 6px;
  border-radius: 4px;
  top: 8px;
}

/* ── Controls panel ──────────────────────────────────────── */
#controls {
  flex: 0 0 auto;
  background: var(--surface);
  border-top: 1px solid var(--border);
  overflow-y: auto;
  padding: 12px 12px 8px;
  max-height: 46vh;
}

.controls-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(175px, 1fr));
  gap: 12px 16px;
}

/* ── Control section ─────────────────────────────────────── */
.ctrl-section { display: flex; flex-direction: column; gap: 6px; }

.ctrl-section h3 {
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--accent);
  padding-bottom: 4px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 2px;
}

/* ── Control row ─────────────────────────────────────────── */
.ctrl-row {
  display: flex;
  align-items: center;
  gap: 8px;
  min-height: 26px;
}

.ctrl-label {
  font-size: 0.78rem;
  color: var(--text-muted);
  min-width: 82px;
  flex-shrink: 0;
}

.ctrl-value {
  font-size: 0.78rem;
  color: var(--text);
  min-width: 64px;
  text-align: right;
  white-space: nowrap;
  flex-shrink: 0;
}

/* ── Inputs ──────────────────────────────────────────────── */
input[type="range"] {
  flex: 1;
  -webkit-appearance: none;
  appearance: none;
  height: 4px;
  background: var(--surface2);
  border-radius: 2px;
  outline: none;
  cursor: pointer;
}
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 16px; height: 16px;
  border-radius: 50%;
  background: var(--accent);
  cursor: pointer;
  border: 2px solid var(--bg);
}
input[type="range"]::-moz-range-thumb {
  width: 16px; height: 16px;
  border-radius: 50%;
  background: var(--accent);
  cursor: pointer;
  border: 2px solid var(--bg);
}
input[type="range"]:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}
input[type="range"]:disabled::-webkit-slider-thumb {
  background: var(--text-muted);
  cursor: not-allowed;
}
input[type="range"]:disabled::-moz-range-thumb {
  background: var(--text-muted);
  cursor: not-allowed;
}

select {
  flex: 1;
  background: var(--surface2);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 5px 8px;
  font-size: 0.82rem;
  cursor: pointer;
  outline: none;
}
select:focus { border-color: var(--accent); }

/* ── Checkboxes ──────────────────────────────────────────── */
.ctrl-check {
  display: flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  font-size: 0.8rem;
  color: var(--text);
  padding: 3px 0;
  user-select: none;
}
.ctrl-check input[type="checkbox"] {
  width: 15px; height: 15px;
  accent-color: var(--accent);
  cursor: pointer;
  flex-shrink: 0;
}

/* ── Buttons ─────────────────────────────────────────────── */
.btn-row { display: flex; gap: 8px; margin-top: 4px; }

.btn {
  flex: 1;
  padding: 8px 6px;
  border: none;
  border-radius: var(--radius);
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
  transition: opacity 0.15s, transform 0.1s;
  white-space: nowrap;
}
.btn:active { transform: scale(0.97); }

.btn-primary   { background: var(--accent);  color: var(--bg); }
.btn-secondary { background: var(--surface2); color: var(--text); border: 1px solid var(--border); }
.btn-danger    { background: var(--danger);   color: #fff; }

/* ── Info bar ────────────────────────────────────────────── */
#info-bar {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 4px 12px;
  background: var(--bg);
  border-top: 1px solid var(--border);
  font-size: 0.74rem;
  color: var(--text-muted);
  flex-shrink: 0;
  flex-wrap: wrap;
}

#info-bar .info-particle {
  color: var(--accent2);
  font-weight: 600;
}

#particle-count { margin-left: auto; color: var(--text-muted); }

/* ── Tablet landscape (side controls) ───────────────────── */
@media (min-width: 768px) and (orientation: landscape),
       (min-width: 1024px) {
  #app { flex-direction: row; }

  #canvas-area {
    flex: 1 1 auto;
    min-width: 0;
    border-right: 1px solid var(--border);
    border-top: none;
  }

  #side-panel {
    display: flex;
    flex-direction: column;
    overflow: hidden;
  }

  #controls {
    flex: 1 1 auto;
    overflow-y: auto;
    border-top: none;
    max-height: none;
  }

  .controls-grid { grid-template-columns: 1fr; }

  #info-bar {
    border-top: 1px solid var(--border);
    border-left: none;
    flex-direction: column;
    align-items: flex-start;
    gap: 4px;
    padding: 8px 12px;
  }

  #particle-count { margin-left: 0; }
}

/* ── Scrollbar ───────────────────────────────────────────── */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }